FIGURE 5.

Stimulation of CD8⁺ T cell proliferation and differentiation into CTL in vivo. Wild-type C57BL/6 or Ia^b−/− gene KO mice were i.v. immunized with irradiated (a) DC_OVA, aT and aT_EXO, and (b) aT_EXO with various gene KO, respectively. Six days after immunization, the tail blood samples of immunized mice were incubated with PE-H-2K^b/OVAI tetramer and FITC-anti-CD8 Ab (Beckman Coulter) according to the company’s protocol, then analyzed by flow cytometry. The value in each panel represents the percentage of tetramer-positive CD8⁺ T cells vs the total CD8⁺ T cell population. The value in parentheses represent the SD. *, p < 0.05 vs cohorts of the positive control (aT/_EXO) (Student’s t test). c, In an in vivo cytotoxicity assay, the above immunized mice were i.v. coinjected at a 1:1 ratio of splenocytes labeled with high (3.0 μM, CFSE^high) and low (0.6 μM, CFSE^low) concentrations of CFSE and pulsed with OVAI and Mut 1 peptide, respectively, 6 days after immunization with aT, aT_EXO, and aT_EXO with various gene KO, respectively. Sixteen hours after target cell delivery, the residual CFSE^high and CFSE^low target cells remaining in the recipients’ spleens were sorted and analyzed by flow cytometry. The value in each panel represents the percentage of CFSE^high cells vs CFSE^low cells remaining in the spleens. *, p < 0.05 vs cohorts of the positive control (aT/EXO_CFSE) (Student’s t test). One representative experiment of three in the above different experiments is shown.